CA1327709C - Silos and methods of burying same - Google Patents
Silos and methods of burying sameInfo
- Publication number
- CA1327709C CA1327709C CA000552390A CA552390A CA1327709C CA 1327709 C CA1327709 C CA 1327709C CA 000552390 A CA000552390 A CA 000552390A CA 552390 A CA552390 A CA 552390A CA 1327709 C CA1327709 C CA 1327709C
- Authority
- CA
- Canada
- Prior art keywords
- sleeve
- fluid
- annular space
- silo
- enlarged
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D5/00—Bulkheads, piles, or other structural elements specially adapted to foundation engineering
- E02D5/66—Mould-pipes or other moulds
- E02D5/665—Mould-pipes or other moulds for making piles
-
- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D23/00—Caissons; Construction or placing of caissons
- E02D23/08—Lowering or sinking caissons
- E02D23/14—Decreasing the skin friction while lowering
Landscapes
- Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Underground Or Underwater Handling Of Building Materials (AREA)
- Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
- Filling Or Emptying Of Bunkers, Hoppers, And Tanks (AREA)
- Road Paving Structures (AREA)
Abstract
ABSTRACT
SILOS AND METHODS OF BURYING SAME
This invention relates to a silo or like structure (16) adapted to be driven end first into the ground comprising an elongate body, wherein the body is enlarged at one end thereof, wherein the enlarged portion carries a cutter (28) directed axially away from the body so as to form an outsize hole for the body when the structure (16) is driven in, wherein duct means (210, 211, 212) are provided for conveying a fluid from a fluid source to the outside of the body behind the enlarged portion, and wherein the structure (16) includes a flexible sleeve (214) attached to the enlarged portion and adapted to cover the body in spaced relationship therefrom, the duct means (210, 211, 212) opening into the annular space defined between the body and the sleeve (214) when the sleeve (214) is in its covering position.
SILOS AND METHODS OF BURYING SAME
This invention relates to a silo or like structure (16) adapted to be driven end first into the ground comprising an elongate body, wherein the body is enlarged at one end thereof, wherein the enlarged portion carries a cutter (28) directed axially away from the body so as to form an outsize hole for the body when the structure (16) is driven in, wherein duct means (210, 211, 212) are provided for conveying a fluid from a fluid source to the outside of the body behind the enlarged portion, and wherein the structure (16) includes a flexible sleeve (214) attached to the enlarged portion and adapted to cover the body in spaced relationship therefrom, the duct means (210, 211, 212) opening into the annular space defined between the body and the sleeve (214) when the sleeve (214) is in its covering position.
Description
~I~Q~ AND MET~QDs DE_BhlY1~4 _~ E
The present invention relates to silos and to methods of burying them, i.e. inserting them in the ground, both on dry land and under water.
By the term "sllo" as u~ed herein is meant any elongate structure, whether hollow or sol~d, open or clo6ed, whlch 1~ adapted to be drlven in end first into the ground.
Although preferably tubular and of ~teel such a silo can be of any shape and of any material whlch cin allow dr~v~ng ln of the silo into the ground either by hydraulic, mechanical or hydrostatic means. For example the' ~llo can be ~qusre in cross-6ectlon, closed at its ~5 upper end ~nd of concrete ln the m~nner of a caisson.
~he 8110 can also take the form of a solld plle which has boen provlded at ~ts lower end wlth a sharp point.
One of tho maln problems encountered during the drlvlnq ln of 81108 into the ground 1~ the frictlon caused by the movement of the sllo w~lls through the 6011. ~S the 8110 i8 drlven deeper into the 80il 50 the area of 6110 wall mov~ng Ag~inst the 80il increaBes ~ and ~urthermore the pros~uro of the surroundlng 8011 again~t the 8110 walls slmllarly lncrea~e~ wlth lncreasing depth of 5ilo penetratlon. Thu~ regardless of the type of 8011 encountered by the ~lo, there 18 generally a limlt to the d-pth of penetratlon achievable by a 8110 for a glven for¢e of 8110 drive.
'~
13~77~
~ c.~,~ 5~4~37 One system for reducing this friction is de~cr~bed ln our ¦
copending UK Patent Application No. 86 21772~(hereinafter referred to as "our copending applicationn). In our copendlng application, the cutting end of t~e 6110 is enlarged around it~ opening so as to form ~n outslze cutting "shoen. The cross-section of the shoe i~
wedge-shaped and the sloping edge of the shoe extends beyond the l~ne of the outside of the silo. By this means the hole cut by the cutting shoe is larger than the profile of the silo and thus an annular space is formed at leAst initially around the 8ilo as it ~s driven in the 8011, there~y reducing the amount and pressure of the ~urrounding 8011 ln contact wlth the sllo wall~ durlng in~ertlon of the silo.
W~th many loose solls and with increasing depth of insertlon, however, the annular ~pace created by the shoe does not stay free of soil foe long, and soil frequently falls lnto the spac~ from the hole s~de~ and friction agaln starts t~ increase.
It has now been found possible to reduce thls inf~lling and resultant friction, and hen¢e permit greater insertlon depths ~or silos, by arranglng for a 1uld to be pumped tnto this annular space.
In accordance with the present ~nvent~on there i8 provlded a ~llo or like structure adapted to be drlven end first lnto the ground comprising an elongate body, wherein the body ~8 enlarged at one end thereof, whereln the enlarged portion carries a cutter directed axially away from the body ~o as to form an outs~ze hole for the body when the structure is driven in, and wherein duct meana are provlded for carrylng ~ flu~d from a fluid ~ource to the outside of the body behind the enlarged portion.
13277~9 The invention also provides a method of inserting a structure of the present ~nventi~n into the ground comprising driving the structure downwardly whilst pumping a fluid from the source to the outside of the body behind the enlarged portion through the duct mean s Preferably the enlarged portion i6 hollow and axlally open and whereln the cutter takes the form of a clrcumferential cutting edge around the opening. Means can then be provided within the body for removin~ ~oil from the lnterlor thereof. In one embodiment the removal means comprise At least one water ~et and a slurry pump, whllst in another the removal means comprises a mechanlcal excavator. Desirably the removal mean3 1~ releasably atta¢hed to the body.
A~ will readily be appreciated by those skllled in the art, the rate of flow of the fluid into the annular space should be at least sufficient to ensure that the whole of the ~pace i8 completely filled throughout the lnsertlon of the ~ilo, thereby helping to support the wall~ of the hole against collap~e. I~ the fluid flow i9 greater than this mlnlmum flow, although the ~low can remove any 80il that has fallen into the annular space and carry lt out of the 8ilo hole 80 a8 to mlnim~ae~infllllng, ~uch extra flow tend~ to create circulating eddies and general turbulence in the annular space whlch erodes the sides of the wall of the hole and lncreases lnfllling, agaln partlcularly 80 wlth lncroasing depth of silo lnsertion.
In order therefore po~itively to prop up the walls of the silo hole and malntaln thi~ annular space ~ubstantially free of 80~1, the silo of the present inventlon includes ln its preferred embodlment a flexible sleeve attached to the enlarged portlon and adapted to cover tha body ln 3paced relationshlp therefrom, the duct means open~ng into the annular space deflned between the body and the sleeve when the sleeve i6 in its covering posltlon. Deslrably the sleeve i6 formed of a porous fabric ~o that at lea6t some of the fluid wlthin the annular space can m~grate to the outer surface of the sleeve and thereby help to reduce the frictlon of the soil against the sleeve itself a6 the 31eeve and silo move lnto the soil. This migrat~on o fluid should, of course, be made up for by a slightly lncreAsed fluid flow lnto the annular space.
In order to withstand the abra~lon of the 80il durlng lnsertlon, lt 13 preferred that the 61eeve be made of a ~o-ca}led "geo-textile" fabric. Such fabrlcs are well known to 8011 englneers.
Slnce the sleeve should cover the silo over e#sentlally the whole o~ its inserted length, elther oub6tantlally the wholo of the silo should be covered rlght from the commenc~ment of its lnsertlon or else, more preferably, \ the sleeve should be arrAnged to unfold progre~sively alons the silo length a~ lnsertion proceeds.
Convenlently ln the latter case means aro provlded for holdlng the ~leeve ln a oonoertlna manner and for allowlng the sleeve to be pulled out durlng drivlng ln o' the ~truoture.
Being supported away rom the 8ilo body predominantly by annular. fluld pressure alono, the sleQve remote from its end~ may have a tendonoy to fall back agalnst the sllo body under the effect of local 8011 pressure, caused for example by dl6placed rocks falllng agalnst the sleeve.
Ono way of counterlng such localised collap~e of the ~loevo 18 to malntaln the ~leeve under tenslon thxoughout the lnsQrtlGn process. Where the ~leeve i6 ~r~t~
.
.
unfolded from, say, a concertlna, thi3 can be achleved by feedlng the sleeve over a plurality of friction roller~, by arranging for succes~lve sections oi the qleeve to be held by shearable connectors, or by providing a plurality of releasing gripping arms on the 6ilo. A second way is to lncorporate into the ~ilo at periodic lntervals along lts length a number of 6upports such as ln the form of rigid clrcumferential bands, for example of plastic3 materlal, po6itioned between the sleeve and the 6110 ln order to hold the Rleeve away from the silo. These band~
can be attached either to the outer surface of the sllo or to the inner ~urface o~ the 61eeve.
The 1uld to be pumped $nto the annular 6pace can comprlse a wlde range of different substances.depending on whether the sllo 18 to be u~ed on dry land or under water, on the nature of the 8011 lnto.whlch the silo is to be ln~erted, on the materlals locally avallable, and on whether or not a sleeve i~ used. ~n addlt~on when a sleeve 18 used, the fluld can either be admitted gradually into the annulus to act essentially aB a ~tagnant pool, or else can be po~ltlvely clrculated through the annulus ~nder pressure.
In the ~ormer case the UppQr end o~ the annulu~ i5 generally open, whllst ln the latter ca~e lt i8 clo~ed wlth outlets near thQ top to take the ~luld back lnslde tho silo ready to be pumped round ~galn through the annulus .
In order to achiQve a ~ood "propplng" ef~ect on the 80il of the hole walls, the ~luid should be unaer r~lat~vely hlgh pre~sure and~or should be o a relatlvely high denslty. Where for example the ~llo i6 to be inserted under water using a sleeve, the fluld can suitably be a mixture oi' compressed air and the ambient water, the alr belng at a pressure substantially higher than the local hydrostat1c head at the maximum aepth of in6ertion of the 13277~9 silo. On dry land u~ing a sleeve, compre~sed alr alone can be u6ed. WheF~ using alr deslr~bly tbe ~leeve ~hould be o~ a material which i6 porou~ to air, thereby allowing some o~ the air tO migrate to the ~ur~ace o the sleeve s and lubricate the same during lnsertion.
In many s~tu~tion~ both with and without A ~leeve the fluid of choice will be an aqueous slurry of a hlgh den61ty inert material such as a clay. A particularly 10 useful clay is bentonite. The maln advantage of using a liquld is that its own hydrostatic head Increases with lncreaslng depth of ingertlon of the silo and counteract~
the lncrease with depth of the soll pressure against the silo. When under WAter, there can also be complete 15 compensatlon using a llquld for the lncreaslng hydrostatlc head with depth of the ambient water. When a sleeve 1~
used lt should preferably be porous either to the ~lurry as a whole or to ju~t the water thereln.
20 Generally lt 18 deslred to aomplete the in~ertion o~ the ~ilo ater drivlng ln to the required ~epth by anchorlng it to the surrounding soil. Although thls can be done by filllng in, or allow to be filled in, the anr~ular space creatod around the sllo durlrg insertlon, lt 18 preferred 25 to pump a hydraullc oement/water slurry from a ~lurry ~ourco to the o~t~lde o the body behlnd the enlarged portlon through the duct means a~ter the structure has been drlven ln to a deslred depth.
30 If the ~llo 1~ to act as a holder or refuge for such thlngs a~ oil well heads, then the hollow, open form o Bilo i8 generally used, the removal of the lngressed 8011 either taklng place durlng lnsertlon - whlch 1~ preerred - or after anchorlng of the 8110. Generally accurate vertical alignment of such silos is required, and this can be achieved by any suitable means. When inserting a silo under water a preferred means for achieving the vertical alignment is the template structure described in our copending application. Other features, such as the buoyancy means, of the under water apparatus described in our copending application can also be used with the silos of the present invention.
One embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings and with reference to the specification consisting of nineteen pages of description and eight pages of drawings filed with our copending application.
In the drawings accompanying this application:-Figure 1 is a sectional elevational view of the lower portion of a rotationally symmetrical silo and excavation module combination of the type described and illustrated in our copending application, but modified in accordance with the present invention for use in underwater excavation, and Figure 2 is a sectional plan view of the silo of Figure 1 taken on the line II-II, with the excavation module removed.
The reference numerals below 200 refer to the reference numerals used in the drawings of our copending application, whilst those above 200 refer to the drawings accompanying this application.
X-- , 13277~9 For the purposes of the present invention the construction and operation of the template/~ilo/ excavation module described and illustrated ln our copending appllcation are as 6et out in our copending application, particularly with reference to Figure 4 thereof, exce~t that the lower ends of ~ilo and excavation module are modifled by the addition of duct me~n~ and a flexible 61eeve, and that the excavatlon ~tep i~Q 61multaneo~1y carried out wth the pumping of a fluid into the annulus formed between the sleeve and the body of the s$10.
Reerring first to Figure 4 of oue copending applicatlon, lt will be noted that the excavation module 36 is separatable from the silo 16. When excavatlng, the module lS 36 1~ located wlthin the silo 16 and exert~ a downward force thereon by means of the engagement of the support rim 58 o~ the module in the ahoulder 34 of the sllo'~ thrust rlng 32. When the duct means of the pre~ent inventlon i8 ~noorporated into the apparatus descrlbed ln our copendlng applicatlon there~ore lt wlll take the form of two duct ey~tems - one ln the excavat~on module and one ln the 8110 lt~elf - fluidly llnked across the support rlm/shoulder ~unatlon.
Referrlng now to Flgures 1 and 2 of the drawing accompanylng thls applicAtlon, the lllu~trated part of the duot ~ystem wlthin the excavat~on module 36 oonsI~t~ of three ring-shaped ~lul~ manlfold~ 201, 202 and 203 for, re~pe~tlvely, alr, water and an aqueous slurry of elther bentonlte or cement running around the perlphory o the transvorse bulkhead 48. Each manlold has a plurallty o~ tran~er tubes 204, 205 and 206, respectlvely, connected thereto to dl~trlbute the fluld~ around the module 36, each transfer tube lesdlng into a respective drllling 207 In the transver~e bulkhe~d 48 before exiting the excavation module ~t ~q ~qc~ t~ tran~fer ~art 20B. ~he . . ;~,.
.: .
13277~
_ 9 _ module trans~er ports 208 are regularly spaced clrcumferentially around the ~upport rim 58 And pro~ect downw~rdly therefrom through the sealing gasket 209 between the module and the ~llo to connect wlth corresponding silo transfer ports 210 located ~n the 6houlder 34.
The man$folds 201 202 and 203 distr~bute thelr respective fluid~ evenly to all of their respective module transfer ports 208, each being supplied at pre66ure from a correspondlng fluid sour¢e (not shown). These fluid sources could lie wlthin the excavation module it6el~ but are geneeally located on the excavation module supply ship. Suitable fluld control means ~not shown) includlng non-return valves (not ghown) are generally provlded to regulate the 10w of the fluld3 out of the~r respective module tran~fer ports 208.
The duct sy~tem wlthln the ~llo 16 cons~sts of a plurality of sllo transfer ports 210 8110 drllllngs 211 into whlch the port~ 210 lead, and 8110 duct outlets 212 at the ends . of the drllllng~ 211. The ~llo transfer ports 210 are spa¢ed around the shoulder 34 and recessed thereln 80 aB
to mate wlth the correspondlng pro~ectlng module transfer 2S ports 208. The 8110 drilllngs 211 run axlally through the thrust rlng 32 and down ln61de the lower wall o the 5110 16 lnto the cuttlng shoe 28. Inslde the outting ~hoe 28 the 8~10 drllllngs turn through 180 to exlt the shoè
upwardly at tbeir a3soc'ated out'et6 212. These outlets 212 are ¢orrespondlngly spaced around the cuttlng shoe 28 and pro~ect ln the form of nozzles upwardly beyond the plane of the horlzontal return face 213 of the shoe 28.
The outlet~ 212 are arranged approximately mldway between the outer edge of the ma~n body of the ~ilo 16 and the outer edge of the shoe 28. The outlets 212 are, like the reBt of the duct me~ns, grouped in threes for the air, water and 3lurry, respectlvely, in order to keep the dlf~erent fluids 6eparate. For example, the alr should be kept dry.
Connected to the return face 213 of the shoe 28 i8 the 1exible ~leeve 214 formed of a fluid permeable geo-textile fabric. The ma~n body of the sleeve 214 run3 concentrlc~lly along the length of the silo 16 but the lower end thereof 18 tùrned lnwardly through 90 50 a8 to be attached by bolts 216 through clamplng ring 217 to the shoe 2B. The annular ~pace 215 lylng between the outer ~urface of the silo 16 and the inner surface o~ the sleeve 214 extends from behlnd the cuttlnq shoes 28 upwardly to cover es~entlally all of the silo 16 that i6 lnserted at that polnt ln time ~nto the seA bed. Towards the upper end of the 8110 fluld inlets ~not shown) can be provlded lf lt 1~ deslred to clrcul~te one of the fluids through the annula~ spAce 21~.
When tho ~llo 16 1B belng lnserted lnto the seA bed, the excAvAtlon module 36 presse~ downwardly on the thrust rlng - 32 of the silo whilst the ex¢avatlon apparAtus tnot ~hown) of tho module remove~ the 8011 from the area wlthln the compas~ o~ the cutting ~hoe 28. Simultaneously wlth thls excavatlon operation, the fluld o ~holce passed under pre~sure from lts ~ource ~not shown) lnto the cocrespondlng manlfold 201, 202 or 203 for dlstrlbutlon vla the duct mean~ ln the module and the ~llo around tho entlre perlphery of the ~llo 16. ~he fluld enters the annular spa~e 215 vla lts set of outlet nozzles 212 and fllls, or 18 reclrculated through, substAntlally the whole of the length thereof wh~ch lles beneath the sea bed.
~he pressure of the fluld withln the ~nnular 8pACe 21 . .
~' ; , . .
m~intain~ the sleeve 214 ~n spaced relation to the 9110 1~, and becau~e o~ the porous nature of the sleeve a s~all proportion of the fluld pa6ses through the sleeve 214 in order to lubricate the outer surface thereor and reduce soil fricti~n thereagainst.
The flu~d control system (not Qhown) regulates the flow of the ~luld into the annular F.~E.c:e 215 in accordance wth the rate of penetration of the cutting ~hoe 28 ~nd the rate of permeation of the fluid through the ~leeve 214. It ~160 enables two or more of the fluids, such as alr and water, to be fed into the space 3 1mUltAneou81y .
It will be appreclated by tho6e 6killed ln the art that the number and orientation of the outlet nozzles 212 can be varied conslderably dependlng on the slze and type of ~llo used, pro~ided that they are po61tioned behlnd the cuttlng shoe 28 60 aB to e~ect the 1u~d into the annular space 215. Furthermore, the construction and disposltion o~ the duct means which conveys ~uch fluid from lt~ source to lt~ outlets 212 can be varied dependlng on the type of ~ilo used. It 1B a1W~Y8 de~lrablo to keep the paths for the three flulds separate, but the cement slurry can be ed th~ough the wator, rAther than bentonite slurry, duct means lf that i8 found to be preferable for A PArtiCU1ar arrangement.
Once the 8ilo 16 has been insQrted to the required depth UBin9, 8ay, A bentonlte slurry ag the annular ~pace 215 filllng 1~1d, the fluld control system ~not shown) can be swltched to pump a hydraulic cement/water slurry tnto the space instead of bentonite. After complete filling of that length of the ~p~ce which lie~ below the sea bed - 12 _ 1 32 77 09 with the cement ~lurry, the control system stops the cement slurry flow and closes all of the one-way valves ln order to prevent back f low thereof out of the annul~r 6pace 215. The excavation module 36 can then be 5 withdrawn from the 1nserted silo 16 and the cement slurry around it allowed to harden. A flrmly lnserted ~llo ls thereby installed to act as a sub 3ea-holder or well head refuge.
'~ 10 lS
~0
The present invention relates to silos and to methods of burying them, i.e. inserting them in the ground, both on dry land and under water.
By the term "sllo" as u~ed herein is meant any elongate structure, whether hollow or sol~d, open or clo6ed, whlch 1~ adapted to be drlven in end first into the ground.
Although preferably tubular and of ~teel such a silo can be of any shape and of any material whlch cin allow dr~v~ng ln of the silo into the ground either by hydraulic, mechanical or hydrostatic means. For example the' ~llo can be ~qusre in cross-6ectlon, closed at its ~5 upper end ~nd of concrete ln the m~nner of a caisson.
~he 8110 can also take the form of a solld plle which has boen provlded at ~ts lower end wlth a sharp point.
One of tho maln problems encountered during the drlvlnq ln of 81108 into the ground 1~ the frictlon caused by the movement of the sllo w~lls through the 6011. ~S the 8110 i8 drlven deeper into the 80il 50 the area of 6110 wall mov~ng Ag~inst the 80il increaBes ~ and ~urthermore the pros~uro of the surroundlng 8011 again~t the 8110 walls slmllarly lncrea~e~ wlth lncreasing depth of 5ilo penetratlon. Thu~ regardless of the type of 8011 encountered by the ~lo, there 18 generally a limlt to the d-pth of penetratlon achievable by a 8110 for a glven for¢e of 8110 drive.
'~
13~77~
~ c.~,~ 5~4~37 One system for reducing this friction is de~cr~bed ln our ¦
copending UK Patent Application No. 86 21772~(hereinafter referred to as "our copending applicationn). In our copendlng application, the cutting end of t~e 6110 is enlarged around it~ opening so as to form ~n outslze cutting "shoen. The cross-section of the shoe i~
wedge-shaped and the sloping edge of the shoe extends beyond the l~ne of the outside of the silo. By this means the hole cut by the cutting shoe is larger than the profile of the silo and thus an annular space is formed at leAst initially around the 8ilo as it ~s driven in the 8011, there~y reducing the amount and pressure of the ~urrounding 8011 ln contact wlth the sllo wall~ durlng in~ertlon of the silo.
W~th many loose solls and with increasing depth of insertlon, however, the annular ~pace created by the shoe does not stay free of soil foe long, and soil frequently falls lnto the spac~ from the hole s~de~ and friction agaln starts t~ increase.
It has now been found possible to reduce thls inf~lling and resultant friction, and hen¢e permit greater insertlon depths ~or silos, by arranglng for a 1uld to be pumped tnto this annular space.
In accordance with the present ~nvent~on there i8 provlded a ~llo or like structure adapted to be drlven end first lnto the ground comprising an elongate body, wherein the body ~8 enlarged at one end thereof, whereln the enlarged portion carries a cutter directed axially away from the body ~o as to form an outs~ze hole for the body when the structure is driven in, and wherein duct meana are provlded for carrylng ~ flu~d from a fluid ~ource to the outside of the body behind the enlarged portion.
13277~9 The invention also provides a method of inserting a structure of the present ~nventi~n into the ground comprising driving the structure downwardly whilst pumping a fluid from the source to the outside of the body behind the enlarged portion through the duct mean s Preferably the enlarged portion i6 hollow and axlally open and whereln the cutter takes the form of a clrcumferential cutting edge around the opening. Means can then be provided within the body for removin~ ~oil from the lnterlor thereof. In one embodiment the removal means comprise At least one water ~et and a slurry pump, whllst in another the removal means comprises a mechanlcal excavator. Desirably the removal mean3 1~ releasably atta¢hed to the body.
A~ will readily be appreciated by those skllled in the art, the rate of flow of the fluid into the annular space should be at least sufficient to ensure that the whole of the ~pace i8 completely filled throughout the lnsertlon of the ~ilo, thereby helping to support the wall~ of the hole against collap~e. I~ the fluid flow i9 greater than this mlnlmum flow, although the ~low can remove any 80il that has fallen into the annular space and carry lt out of the 8ilo hole 80 a8 to mlnim~ae~infllllng, ~uch extra flow tend~ to create circulating eddies and general turbulence in the annular space whlch erodes the sides of the wall of the hole and lncreases lnfllling, agaln partlcularly 80 wlth lncroasing depth of silo lnsertion.
In order therefore po~itively to prop up the walls of the silo hole and malntaln thi~ annular space ~ubstantially free of 80~1, the silo of the present inventlon includes ln its preferred embodlment a flexible sleeve attached to the enlarged portlon and adapted to cover tha body ln 3paced relationshlp therefrom, the duct means open~ng into the annular space deflned between the body and the sleeve when the sleeve i6 in its covering posltlon. Deslrably the sleeve i6 formed of a porous fabric ~o that at lea6t some of the fluid wlthin the annular space can m~grate to the outer surface of the sleeve and thereby help to reduce the frictlon of the soil against the sleeve itself a6 the 31eeve and silo move lnto the soil. This migrat~on o fluid should, of course, be made up for by a slightly lncreAsed fluid flow lnto the annular space.
In order to withstand the abra~lon of the 80il durlng lnsertlon, lt 13 preferred that the 61eeve be made of a ~o-ca}led "geo-textile" fabric. Such fabrlcs are well known to 8011 englneers.
Slnce the sleeve should cover the silo over e#sentlally the whole o~ its inserted length, elther oub6tantlally the wholo of the silo should be covered rlght from the commenc~ment of its lnsertlon or else, more preferably, \ the sleeve should be arrAnged to unfold progre~sively alons the silo length a~ lnsertion proceeds.
Convenlently ln the latter case means aro provlded for holdlng the ~leeve ln a oonoertlna manner and for allowlng the sleeve to be pulled out durlng drivlng ln o' the ~truoture.
Being supported away rom the 8ilo body predominantly by annular. fluld pressure alono, the sleQve remote from its end~ may have a tendonoy to fall back agalnst the sllo body under the effect of local 8011 pressure, caused for example by dl6placed rocks falllng agalnst the sleeve.
Ono way of counterlng such localised collap~e of the ~loevo 18 to malntaln the ~leeve under tenslon thxoughout the lnsQrtlGn process. Where the ~leeve i6 ~r~t~
.
.
unfolded from, say, a concertlna, thi3 can be achleved by feedlng the sleeve over a plurality of friction roller~, by arranging for succes~lve sections oi the qleeve to be held by shearable connectors, or by providing a plurality of releasing gripping arms on the 6ilo. A second way is to lncorporate into the ~ilo at periodic lntervals along lts length a number of 6upports such as ln the form of rigid clrcumferential bands, for example of plastic3 materlal, po6itioned between the sleeve and the 6110 ln order to hold the Rleeve away from the silo. These band~
can be attached either to the outer surface of the sllo or to the inner ~urface o~ the 61eeve.
The 1uld to be pumped $nto the annular 6pace can comprlse a wlde range of different substances.depending on whether the sllo 18 to be u~ed on dry land or under water, on the nature of the 8011 lnto.whlch the silo is to be ln~erted, on the materlals locally avallable, and on whether or not a sleeve i~ used. ~n addlt~on when a sleeve 18 used, the fluld can either be admitted gradually into the annulus to act essentially aB a ~tagnant pool, or else can be po~ltlvely clrculated through the annulus ~nder pressure.
In the ~ormer case the UppQr end o~ the annulu~ i5 generally open, whllst ln the latter ca~e lt i8 clo~ed wlth outlets near thQ top to take the ~luld back lnslde tho silo ready to be pumped round ~galn through the annulus .
In order to achiQve a ~ood "propplng" ef~ect on the 80il of the hole walls, the ~luid should be unaer r~lat~vely hlgh pre~sure and~or should be o a relatlvely high denslty. Where for example the ~llo i6 to be inserted under water using a sleeve, the fluld can suitably be a mixture oi' compressed air and the ambient water, the alr belng at a pressure substantially higher than the local hydrostat1c head at the maximum aepth of in6ertion of the 13277~9 silo. On dry land u~ing a sleeve, compre~sed alr alone can be u6ed. WheF~ using alr deslr~bly tbe ~leeve ~hould be o~ a material which i6 porou~ to air, thereby allowing some o~ the air tO migrate to the ~ur~ace o the sleeve s and lubricate the same during lnsertion.
In many s~tu~tion~ both with and without A ~leeve the fluid of choice will be an aqueous slurry of a hlgh den61ty inert material such as a clay. A particularly 10 useful clay is bentonite. The maln advantage of using a liquld is that its own hydrostatic head Increases with lncreaslng depth of ingertlon of the silo and counteract~
the lncrease with depth of the soll pressure against the silo. When under WAter, there can also be complete 15 compensatlon using a llquld for the lncreaslng hydrostatlc head with depth of the ambient water. When a sleeve 1~
used lt should preferably be porous either to the ~lurry as a whole or to ju~t the water thereln.
20 Generally lt 18 deslred to aomplete the in~ertion o~ the ~ilo ater drivlng ln to the required ~epth by anchorlng it to the surrounding soil. Although thls can be done by filllng in, or allow to be filled in, the anr~ular space creatod around the sllo durlrg insertlon, lt 18 preferred 25 to pump a hydraullc oement/water slurry from a ~lurry ~ourco to the o~t~lde o the body behlnd the enlarged portlon through the duct means a~ter the structure has been drlven ln to a deslred depth.
30 If the ~llo 1~ to act as a holder or refuge for such thlngs a~ oil well heads, then the hollow, open form o Bilo i8 generally used, the removal of the lngressed 8011 either taklng place durlng lnsertlon - whlch 1~ preerred - or after anchorlng of the 8110. Generally accurate vertical alignment of such silos is required, and this can be achieved by any suitable means. When inserting a silo under water a preferred means for achieving the vertical alignment is the template structure described in our copending application. Other features, such as the buoyancy means, of the under water apparatus described in our copending application can also be used with the silos of the present invention.
One embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings and with reference to the specification consisting of nineteen pages of description and eight pages of drawings filed with our copending application.
In the drawings accompanying this application:-Figure 1 is a sectional elevational view of the lower portion of a rotationally symmetrical silo and excavation module combination of the type described and illustrated in our copending application, but modified in accordance with the present invention for use in underwater excavation, and Figure 2 is a sectional plan view of the silo of Figure 1 taken on the line II-II, with the excavation module removed.
The reference numerals below 200 refer to the reference numerals used in the drawings of our copending application, whilst those above 200 refer to the drawings accompanying this application.
X-- , 13277~9 For the purposes of the present invention the construction and operation of the template/~ilo/ excavation module described and illustrated ln our copending appllcation are as 6et out in our copending application, particularly with reference to Figure 4 thereof, exce~t that the lower ends of ~ilo and excavation module are modifled by the addition of duct me~n~ and a flexible 61eeve, and that the excavatlon ~tep i~Q 61multaneo~1y carried out wth the pumping of a fluid into the annulus formed between the sleeve and the body of the s$10.
Reerring first to Figure 4 of oue copending applicatlon, lt will be noted that the excavation module 36 is separatable from the silo 16. When excavatlng, the module lS 36 1~ located wlthin the silo 16 and exert~ a downward force thereon by means of the engagement of the support rim 58 o~ the module in the ahoulder 34 of the sllo'~ thrust rlng 32. When the duct means of the pre~ent inventlon i8 ~noorporated into the apparatus descrlbed ln our copendlng applicatlon there~ore lt wlll take the form of two duct ey~tems - one ln the excavat~on module and one ln the 8110 lt~elf - fluidly llnked across the support rlm/shoulder ~unatlon.
Referrlng now to Flgures 1 and 2 of the drawing accompanylng thls applicAtlon, the lllu~trated part of the duot ~ystem wlthin the excavat~on module 36 oonsI~t~ of three ring-shaped ~lul~ manlfold~ 201, 202 and 203 for, re~pe~tlvely, alr, water and an aqueous slurry of elther bentonlte or cement running around the perlphory o the transvorse bulkhead 48. Each manlold has a plurallty o~ tran~er tubes 204, 205 and 206, respectlvely, connected thereto to dl~trlbute the fluld~ around the module 36, each transfer tube lesdlng into a respective drllling 207 In the transver~e bulkhe~d 48 before exiting the excavation module ~t ~q ~qc~ t~ tran~fer ~art 20B. ~he . . ;~,.
.: .
13277~
_ 9 _ module trans~er ports 208 are regularly spaced clrcumferentially around the ~upport rim 58 And pro~ect downw~rdly therefrom through the sealing gasket 209 between the module and the ~llo to connect wlth corresponding silo transfer ports 210 located ~n the 6houlder 34.
The man$folds 201 202 and 203 distr~bute thelr respective fluid~ evenly to all of their respective module transfer ports 208, each being supplied at pre66ure from a correspondlng fluid sour¢e (not shown). These fluid sources could lie wlthin the excavation module it6el~ but are geneeally located on the excavation module supply ship. Suitable fluld control means ~not shown) includlng non-return valves (not ghown) are generally provlded to regulate the 10w of the fluld3 out of the~r respective module tran~fer ports 208.
The duct sy~tem wlthln the ~llo 16 cons~sts of a plurality of sllo transfer ports 210 8110 drllllngs 211 into whlch the port~ 210 lead, and 8110 duct outlets 212 at the ends . of the drllllng~ 211. The ~llo transfer ports 210 are spa¢ed around the shoulder 34 and recessed thereln 80 aB
to mate wlth the correspondlng pro~ectlng module transfer 2S ports 208. The 8110 drilllngs 211 run axlally through the thrust rlng 32 and down ln61de the lower wall o the 5110 16 lnto the cuttlng shoe 28. Inslde the outting ~hoe 28 the 8~10 drllllngs turn through 180 to exlt the shoè
upwardly at tbeir a3soc'ated out'et6 212. These outlets 212 are ¢orrespondlngly spaced around the cuttlng shoe 28 and pro~ect ln the form of nozzles upwardly beyond the plane of the horlzontal return face 213 of the shoe 28.
The outlet~ 212 are arranged approximately mldway between the outer edge of the ma~n body of the ~ilo 16 and the outer edge of the shoe 28. The outlets 212 are, like the reBt of the duct me~ns, grouped in threes for the air, water and 3lurry, respectlvely, in order to keep the dlf~erent fluids 6eparate. For example, the alr should be kept dry.
Connected to the return face 213 of the shoe 28 i8 the 1exible ~leeve 214 formed of a fluid permeable geo-textile fabric. The ma~n body of the sleeve 214 run3 concentrlc~lly along the length of the silo 16 but the lower end thereof 18 tùrned lnwardly through 90 50 a8 to be attached by bolts 216 through clamplng ring 217 to the shoe 2B. The annular ~pace 215 lylng between the outer ~urface of the silo 16 and the inner surface o~ the sleeve 214 extends from behlnd the cuttlnq shoes 28 upwardly to cover es~entlally all of the silo 16 that i6 lnserted at that polnt ln time ~nto the seA bed. Towards the upper end of the 8110 fluld inlets ~not shown) can be provlded lf lt 1~ deslred to clrcul~te one of the fluids through the annula~ spAce 21~.
When tho ~llo 16 1B belng lnserted lnto the seA bed, the excAvAtlon module 36 presse~ downwardly on the thrust rlng - 32 of the silo whilst the ex¢avatlon apparAtus tnot ~hown) of tho module remove~ the 8011 from the area wlthln the compas~ o~ the cutting ~hoe 28. Simultaneously wlth thls excavatlon operation, the fluld o ~holce passed under pre~sure from lts ~ource ~not shown) lnto the cocrespondlng manlfold 201, 202 or 203 for dlstrlbutlon vla the duct mean~ ln the module and the ~llo around tho entlre perlphery of the ~llo 16. ~he fluld enters the annular spa~e 215 vla lts set of outlet nozzles 212 and fllls, or 18 reclrculated through, substAntlally the whole of the length thereof wh~ch lles beneath the sea bed.
~he pressure of the fluld withln the ~nnular 8pACe 21 . .
~' ; , . .
m~intain~ the sleeve 214 ~n spaced relation to the 9110 1~, and becau~e o~ the porous nature of the sleeve a s~all proportion of the fluld pa6ses through the sleeve 214 in order to lubricate the outer surface thereor and reduce soil fricti~n thereagainst.
The flu~d control system (not Qhown) regulates the flow of the ~luld into the annular F.~E.c:e 215 in accordance wth the rate of penetration of the cutting ~hoe 28 ~nd the rate of permeation of the fluid through the ~leeve 214. It ~160 enables two or more of the fluids, such as alr and water, to be fed into the space 3 1mUltAneou81y .
It will be appreclated by tho6e 6killed ln the art that the number and orientation of the outlet nozzles 212 can be varied conslderably dependlng on the slze and type of ~llo used, pro~ided that they are po61tioned behlnd the cuttlng shoe 28 60 aB to e~ect the 1u~d into the annular space 215. Furthermore, the construction and disposltion o~ the duct means which conveys ~uch fluid from lt~ source to lt~ outlets 212 can be varied dependlng on the type of ~ilo used. It 1B a1W~Y8 de~lrablo to keep the paths for the three flulds separate, but the cement slurry can be ed th~ough the wator, rAther than bentonite slurry, duct means lf that i8 found to be preferable for A PArtiCU1ar arrangement.
Once the 8ilo 16 has been insQrted to the required depth UBin9, 8ay, A bentonlte slurry ag the annular ~pace 215 filllng 1~1d, the fluld control system ~not shown) can be swltched to pump a hydraulic cement/water slurry tnto the space instead of bentonite. After complete filling of that length of the ~p~ce which lie~ below the sea bed - 12 _ 1 32 77 09 with the cement ~lurry, the control system stops the cement slurry flow and closes all of the one-way valves ln order to prevent back f low thereof out of the annul~r 6pace 215. The excavation module 36 can then be 5 withdrawn from the 1nserted silo 16 and the cement slurry around it allowed to harden. A flrmly lnserted ~llo ls thereby installed to act as a sub 3ea-holder or well head refuge.
'~ 10 lS
~0
Claims (9)
1. A silo or like structure adapted to be inserted end first into the ground to a desired depth comprising an elongate body enlarged at one end, a cutter carried by the enlarged end and directed axially away from the body so as to form an outsize hole for the body when the structure is inserted into the ground, a flexible sleeve attached to the periphery of the enlarged end, and duct means opening into an annular space defined between the body and the sleeve for conveying a fluid from a fluid source into said annular space characterized in that the flexible sleeve is adapted to cover essentially the entire inserted length of the body in spaced relationship therefrom, and in that the sleeve is porous with respect to the said fluid, whereby the pressure of said fluid conveyed in said annular space maintains the sleeve in said spaced relationship and the porosity of the sleeve permits a small proportion of said fluid to pass through the sleeve in order to lubricate the outer surface thereof and reduce soil friction thereagainst as the structure is inserted into the ground.
2. A structure as claimed in claim 1 wherein the enlarged end is hollow and axially open and wherein the cutter takes the form of a circumferential cutting edge around the opening of said enlarged end.
3. A structure as claimed in claim 1 wherein the sleeve is formed of a porous fabric.
4. A structure as claimed in claim 1 including at least one sleeve support for maintaining the sleeve in spaced relationship to the body.
5. A structure as claimed in claim 1 which is adapted to be inserted into an underwater sea bed.
6. A method of inserting a silo or like structure end first into the group to a desired depth which structure comprises an elongate body enlarged at one end, a cutter carried by the enlarged end and directed axially away from the body so as to form an outsize hole for the body when the structure is inserted into the ground, a flexible sleeve attached to the periphery of the enlarged end, and duct means opening into an annular space defined between the body and the sleeve for conveying a fluid from a fluid source to the annular space, wherein the flexible sleeve is adapted to cover essentially the entire inserted length of the body in space relationship therefrom, and wherein the sleeve is porous with respect to said fluid, the method comprising driving the structure downwardly whilst pumping a fluid from the source into the annular space between the body and the sleeve through the duct means; maintaining the sleeve in the spaced relationship with respect to the body; and permitting a small proportion of the fluid to pass through the porous sleeve in order to lubricate the outer surface thereof and reduce friction thereagainst.
7. A method as claimed in claim 6 wherein the fluid is an air/water mixture.
8. A method as claimed in claim 6 wherein the fluid is an aqueous slurry of bentonite.
9. A method as claimed in claim 6, 7 or 8 including the steps of pumping a hydraulic cement/water slurry from a slurry source into the annular space between the body and the sleeve through the duct means after the structure has been driven in to a desired depth, and allowing the slurry to set around the structure.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB868627738A GB8627738D0 (en) | 1986-11-20 | 1986-11-20 | Silos |
| GB8627738 | 1986-11-20 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1327709C true CA1327709C (en) | 1994-03-15 |
Family
ID=10607635
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000552390A Expired - Fee Related CA1327709C (en) | 1986-11-20 | 1987-11-20 | Silos and methods of burying same |
Country Status (12)
| Country | Link |
|---|---|
| US (1) | US4973197A (en) |
| EP (1) | EP0268500B1 (en) |
| AU (1) | AU604516B2 (en) |
| BR (1) | BR8707887A (en) |
| CA (1) | CA1327709C (en) |
| DE (1) | DE3766802D1 (en) |
| DK (1) | DK159625C (en) |
| ES (1) | ES2019643B3 (en) |
| FI (1) | FI90898C (en) |
| GB (1) | GB8627738D0 (en) |
| GR (1) | GR3002546T3 (en) |
| WO (1) | WO1988003975A1 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2264733B (en) * | 1992-03-03 | 1995-10-18 | British Gas Plc | Apparatus intended to be buried in ground beneath water |
| FR2769323B1 (en) | 1997-10-08 | 2001-07-13 | Suez Lyonnaise Des Eaux | MEANS FOR THE QUALITATIVE AND QUANTITATIVE ANALYSIS OF THE MICROBIAL POPULATIONS POSSIBLY PRESENT IN A SAMPLE |
| US6616380B1 (en) * | 2002-06-03 | 2003-09-09 | Matthew F. Russell | Subterranean structures and methods for constructing subterranean structures |
| JP6552204B2 (en) * | 2015-01-28 | 2019-07-31 | 大成建設株式会社 | Caisson settling method and friction cut structure |
| JP6764691B2 (en) * | 2016-05-24 | 2020-10-07 | 前田建設工業株式会社 | Caisson skeleton subsidence device |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE352971C (en) * | 1922-05-11 | Masteroll Perforating Machine | Machine for punching music tapes | |
| GB260143A (en) * | 1926-01-25 | 1926-10-28 | Yulee Alison Dyer | Improvements in methods of melting iron and other metals |
| US2065003A (en) * | 1933-12-11 | 1936-12-22 | Widugier Edward | Means for building deep foundations |
| GB692227A (en) * | 1950-03-11 | 1953-06-03 | Hans Lorenz | Process for the production and sinking of caissons of any desired form |
| CH352971A (en) * | 1957-04-18 | 1961-03-15 | Grundwasserbauten Ag F | Process for the production of structures and sink structures protruding into the ground for carrying out this process |
| DE1222442B (en) * | 1962-01-05 | 1966-08-04 | Richard Schulz | Process for reducing the sliding resistance when driving or lowering building structures or auxiliary building devices in the ground and driving or lowering bodies for carrying out the process |
| US3293865A (en) * | 1963-05-27 | 1966-12-27 | Robert L Loofbourow | System for lining large diameter bore holes |
| US3492823A (en) * | 1967-03-30 | 1970-02-03 | Tech Inc Const | Method and apparatus for forming elongated hardened concrete bodies by pressure grouting |
| DE1941993B2 (en) * | 1969-08-18 | 1972-03-23 | DEVICE FOR PAINTING IN COMPONENTS | |
| FR2217969A5 (en) * | 1973-02-12 | 1974-09-06 | Soletanche | |
| DE2544834C3 (en) * | 1975-10-07 | 1982-04-22 | Gewerkschaft Walter, 4300 Essen | Device for sinking shafts in unstable rock |
| US4585681A (en) * | 1983-06-03 | 1986-04-29 | Nippon Kokan Kk | Frost damage proofed pile |
| DE3326246A1 (en) * | 1983-07-21 | 1985-01-31 | Paul 5940 Lennestadt Schmidt | RAMM DEVICE |
-
1986
- 1986-11-20 GB GB868627738A patent/GB8627738D0/en active Pending
-
1987
- 1987-11-20 AU AU82726/87A patent/AU604516B2/en not_active Ceased
- 1987-11-20 DE DE8787310302T patent/DE3766802D1/en not_active Expired - Fee Related
- 1987-11-20 CA CA000552390A patent/CA1327709C/en not_active Expired - Fee Related
- 1987-11-20 BR BR8707887A patent/BR8707887A/en not_active IP Right Cessation
- 1987-11-20 EP EP87310302A patent/EP0268500B1/en not_active Expired - Lifetime
- 1987-11-20 ES ES87310302T patent/ES2019643B3/en not_active Expired - Lifetime
- 1987-11-20 US US07/359,660 patent/US4973197A/en not_active Expired - Fee Related
- 1987-11-20 WO PCT/GB1987/000829 patent/WO1988003975A1/en active IP Right Grant
-
1988
- 1988-07-19 DK DK401888A patent/DK159625C/en not_active IP Right Cessation
-
1989
- 1989-05-19 FI FI892422A patent/FI90898C/en not_active IP Right Cessation
-
1990
- 1990-12-20 GR GR90400475T patent/GR3002546T3/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DK159625B (en) | 1990-11-05 |
| AU604516B2 (en) | 1990-12-20 |
| FI90898C (en) | 1994-04-11 |
| BR8707887A (en) | 1989-10-31 |
| DE3766802D1 (en) | 1991-01-31 |
| WO1988003975A1 (en) | 1988-06-02 |
| FI892422A0 (en) | 1989-05-19 |
| GB8627738D0 (en) | 1987-01-21 |
| GR3002546T3 (en) | 1993-01-25 |
| EP0268500A1 (en) | 1988-05-25 |
| FI892422A (en) | 1989-05-19 |
| US4973197A (en) | 1990-11-27 |
| EP0268500B1 (en) | 1990-12-19 |
| AU8272687A (en) | 1988-06-16 |
| ES2019643B3 (en) | 1991-07-01 |
| FI90898B (en) | 1993-12-31 |
| DK159625C (en) | 1991-04-08 |
| DK401888D0 (en) | 1988-07-19 |
| DK401888A (en) | 1988-09-20 |
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